Accession Number : AD0450753


Title :   RESPONSES TO ADRENALINE AND NORADRENALINE IN CATS DURING HYPOXIA, HYPERVENTILATION AND HYPEROXIA,


Corporate Author : UNIVERSITY OF WESTERN ONTARIO LONDON


Personal Author(s) : Gowdey, C W ; Patel, Y J


Report Date : 23 Jul 1963


Pagination or Media Count : 39


Abstract : This investigation showed that the pressor responses to i.v. injections of adrenaline and noradrenaline were significantly reduced in spinal cats during hypoventilation-induced hypoxia and acidosis. Similar reductions were found in anaesthetized cats made hypoxic by decompression to a simulated altitude of 20,000 feet. Hyperventilation-induced hypocapnia and alkalosis also reduced the pressor responsed to injected catecholamines in spinal cats. When hypocapnia was prevented by hyperventilating with 5% CO2, the pressor responses were not markedly different from those during optimal ventilation. Hyperoxia did not modify the pressor responses to injected adrenaline or noradrenaline. The contractions of the nictitating membrane evoked by adrenaline were larger during hyperventilation and smaller during hypoventilation than those during optimal ventilation. During hypoxia with or without acidosis the reduced responses of the cardiovascular system and the nictitating membrane to injected catecholamines may be explained by the depressing effect of hypoxia on the tissues themselves even though the autonomic centres may be temporarily stimulated and produce an increased peripheral resistance. (Author)


Descriptors :   *CARDIOVASCULAR AGENTS , RESPIRATION , NOREPINEPHRINE , HYPOXIA , VENTILATION , PRESSURE BREATHING , BLOOD PRESSURE , SIMULATION , HIGH ALTITUDE , ACIDOSIS , BIOCHEMISTRY , PHARMACOLOGY , PHYSIOLOGY


Distribution Statement : APPROVED FOR PUBLIC RELEASE